(1) Field of the Invention
The present invention relates to doors, and is more particularly concerned with a door having outer sheet metal skins and a foamed-in-place core.
(2) Prior Art
It was formerly conventional to construct doors with a wood frame and wood paneling. It was then customary for the carpenter working on the job site to drill a transverse bore to receive the lockset and to drill a bore in the edge of the door communicating with the first bore to house the bolt. In order that the lock be operational, it was necessary for both the lock cylinder bore and the bolt bore to be drilled with extremely high precision. Moreover, it was necessary to utilize special tools for this process.
Eventually, many doors were made of steel sheets forming spaced-apart skins with foamed-in-place cores formed between the skins. The problem of providing bores for the lockset and the bolt became more acute since it was difficult to provide precision placed openings in the steel skins and also in the core at the job site. It then became conventional to provide precut apertures in the door for both the lock cylinder and the bolt. However, it then became necessary to retain lock cylinder and bolt chambers free of foam when the core was foamed in-place.
In U.S. Pat. No. 4,118,985 there is disclosed a liner to be inserted in a door to provide the lock cylinder and bolt chambers and to provide for the chambers to remain free of foam after the space between the skins are filled with foam. The structure comprises a tube having its axis positioned transverse to the skins and a second and smaller tube formed in the side wall of the larger tube and positioned radially therefrom. The large tube is retained between the skins and the small tube is inserted through an aperture provided in the edge of the door. This structure performs the task for which it was designed. However, there is no means provided for fastening the structure to the door prior to foaming except for the insertion of the small radial tube into the edge bore of the door. Moreover, the insert must be formed by injection molding of a plastic material. Both the process and the dies necessary for carrying out the process are very expensive.